The present application relates generally to office machines. More particularly, it relates to an improved cleaning device for an electrostatographic printing machine.
The invention is particularly suited for use in cleaning a photoreceptor device such as a belt or drum of an electrostatographic printing machine. However, it should be appreciated that the apparatus could also be used in many other types of office machines.
In electrostatographic printing apparatus commonly used today, a photoconductive insulating member is typically charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in the exposed or background areas and creates an electrostatic latent image on the member which corresponds to the image contained within the original document. Alternatively, a light beam may be modulated and used to selectively discharge portions of the charged photoconductive surface to record the desired information thereon. Typically, such a system employs a laser beam. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with developer powder referred to in the art as toner. Most development systems employ developer which comprises both charged carrier particles and charged toner particles which triboelectrically adhere to the carrier particles. During development, the toner particles are attracted from the carrier particles by the charged pattern of the image areas of the photoconductive insulating area to form a powder image on the photoconductive area. This toner image may be subsequently transferred to a support surface, such as copy paper, to which it may be permanently affixed by heating or by the application of pressure.
In commercial applications of such products, it is necessary to clean the photoreceptor belt or drum after the print has been made in order to prepare the photoreceptor device for the next print cycle. Cleaning of the photoreceptor belt or drum includes two steps. First, the residual image needs to be removed from the photoreceptor device. The residual image is the toner image which remains on the photoreceptor device after the transfer process. Second, any remaining charge on the photoreceptor device must be removed. This requirement insures that the photoreceptor device starts the next print cycle electrically neutral. Toner is usually removed from the photoreceptor belt or drum by scraping its surface with a blade.
Conventional blades are flexible, usually made of rubber or synthetic material and contact the photoreceptor surface at an angle so that toner is physically scraped off the photoreceptor. One difficulty with such conventional cleaning blades is that the blade needs to be replaced after a period of time. This in turn necessitates removing the machine from operation while the cleaning blade is replaced. In addition, with conventional cleaning blades, in order to insure that the blade lasts as long as possible, a relatively expensive material needs to be utilized for the cleaning blade.
Accordingly, it has been considered desirable to develop a new and improved cleaning blade assembly which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.